As long as I can understand java api, opening a RandomAccessFile using "rw" does not write ervery single byte synchronously on the underlying storage device. Unlike with "rws" or "rwd".
Why is it almost the same "speed" like the unbuffered FileOutputStream with "rw" and more than 10 times slower with "rws"/"rwd"?

the following simple code shows this, and I cannot get any reasonnable explanation to this. Any clue?